Boris Johnson has admitted he wrote a rap on the Queen's silver jubilee.
The London Mayor - who met Will Smith at a celebration for Mr Johnson's Leadership Clubs, which offer extracurricular activities for 10 to 14-year-olds - told the Hollywood actor: "My first rap, I haven't really set it to music yet. Perhaps with your help. I can send you a lyric. It was about the Queen's silver jubilee."
Smith joked: "That was big in the hip-hop community."
The pair also share Aristotle's Poetics as an inspiration and Mr Johnson said: "Aristotle's book could be called the Pursuit Of Happiness," referencing Smith's Hollywood hit. Smith replied: "It's very big for film. You see, we've got a lot in common."
Smith and his son Jaden were surprise guests for the 90 children taking part in the workshops. The father and son arrived to the trailer of their new film, After Earth, with Jaden performing a spontaneous rap for the children.
He spoke about working with his father and said: "He has, as you can see, all the experience you ever need. So if you ever need anything on set, you can just walk over and ask him. He's like a walking dictionary. Any time I'm lost or anything, I can just ask him."
The 14-year-old actor and rapper named Shakespeare and Kanye West among his greatest influences and said he would never tell his father if he became more successful than him. He said: "Even if I did it, I would never say it."
The pair joined in the children's activities, even making a "human knot" with them, where Smith joked: "I think I've pulled a muscle." Speaking about the day, he said: "This was fantastic and I think it's hugely important to take these moments."
Mr Johnson added: "I was totally out of my depth there when we did the rapping stuff but it's fantastic, really wonderful Will and Jaden have given up their time to come here and electrify these kids. This is something they are going to remember for a very long time, if not the rest of their lives.
"The idea is that leadership clubs are things that inspire you to do great things in your life. Maybe you're not going to be Will Smith and Jaden but everyone's got something fantastic in them."